Cryogenian sterane records used on the Demospongiae route are a contested geochemical attribution to sponge-grade sources; they do not establish a demosponge crown origin, body fossil or global first appearance.
claim:taxon:demospongiaeDemospongiae
Cryogenian sterane records used on the Demospongiae route are a contested geochemical attribution to sponge-grade sources; they do not establish a demosponge crown origin, body fossil or global first appearance. This navigation entry is not a phylogeny or a complete taxon dossier.
Represented range635–Present Ma
Content packagesponges-cnidarians
PBDBtxn:2895
Evidence boundary
Automated checks cover structure, identifiers, translations and links only; maintainer and external expert review are not complete.
Claim ledger
Demospongiae is displayed at 635–0 Ma only as a contested biomarker-to-living navigation anthology: Cryogenian 24-isopropylcholestanes are not taxonomically exclusive to demosponges and do not establish a body-fossil FAD, crown origin or continuous global occupancy.
claim:taxon:demospongiae:range-boundary-rc50Known limits
- A missing branch or fossil occurrence does not imply biological absence. Internal nodes are not calibrated divergence estimates.
References
- Fossil steroids record the appearance of Demospongiae during the Cryogenian periodLove, G.D.; Grosjean, E.; Stalvies, C.; Fike, D.A.; Grotzinger, J.P.; Bradley, A.S.; Kelly, A.E.; Bhatia, M.; Meredith, W.; Snape, C.E.; Bowring, S.A.; Condon, D.J.; Summons, R.E. · 2009 · DOI 10.1038/nature07673
- Putative sponge biomarkers in unicellular Rhizaria question an early rise of animalsNettersheim, B.J.; Brocks, J.J.; Schwelm, A.; Hope, J.M.; Not, F.; Lomas, M.; Schmidt, C.; Schiebel, R.; Nowack, E.C.M.; De Deckker, P.; et al. · 2019 · DOI 10.1038/s41559-019-0806-5
- Open Tree of Life web servicesOpenTreeOfLife Project
- The Paleobiology Database application programming interfacePeters, S.E.; McClennen, M. · 2016 · DOI 10.1017/pab.2015.39
- Denormalized occurrence and taxon tables of the Paleobiology DatabaseThe Paleobiology Database Community; Kocsis, Á.T. · 2026 · DOI 10.5281/zenodo.21620933